REAL ESTATE AND OTHER AFFILIATES (Narrative) (Details)				1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
	Jun. 01, 2016 a	Jan. 24, 2014 USD ($) a item	Oct. 04, 2013 USD ($) a	Jan. 31, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($) item	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Real Estate and Other Affiliates
Gain recognized on the sale of Redlands Promenade									$ 32,452,000	$ 140,549,000
Equity in earnings					$ 7,467,000	$ 13,493,000			25,821,000	35,700,000
The Summit
Real Estate and Other Affiliates
Preferred return, on capital (as a percent)								5.00%
Entitlement of distribution by joint venture (in times) | item								2
Return on capital contributions (as a percent)								100.00%
Total assets					163,600				163,600		$ 151,300
Total liabilities					107,300				107,300		116,500
Equity					56,300				56,300		34,800
Revenues					14,200	24,700			46,300	41,600
Gross margin					6,500	13,700			21,600	22,600
Net income					7,700	14,600			26,400	25,100
33 Peck Slip (Grandview SHG, LLC) [Member]
Real Estate and Other Affiliates
Payments to Acquire Interest in Joint Venture					700,000	2,300,000
Capital contribution				$ 6,000,000
Investment in joint venture					$ 9,100,000				$ 9,100,000
33 Peck Slip (Grandview SHG, LLC) [Member] | Bridge Loan [Member]
Real Estate and Other Affiliates
Interest rate margin (as a percent)				5.00%
Amount of bridge loan				$ 25,000,000
33 Peck Slip (Grandview SHG, LLC) [Member] | Construction Loan Payable [Member]
Real Estate and Other Affiliates
Redevelopment loan						$ 36,000,000				36,000,000
m.flats/TEN.M
Real Estate and Other Affiliates
Transaction value of the land contributed to joint venture			$ 23,400,000
Area of land contributed to the joint venture (in acres) | a			5
Fair value of the land contributed to joint venture			$ 4,000,000
Additional capitalized development costs incurred resulting from contribution of land			3,100,000
Total book value contribution			7,100,000
Transaction value, per constructed unit of land contributed to joint venture			$ 53,500
Distribution of the cash contributed by joint venture partner				7,300,000
Contribution made till date											6,300,000
Gain recognized on the sale of Redlands Promenade											$ 200,000
m.flats/TEN.M | Kettler Inc
Real Estate and Other Affiliates
Payments to Acquire Interest in Joint Venture				16,100,000
m.flats/TEN.M | Construction Loan Payable [Member]
Real Estate and Other Affiliates
Non-recourse construction loan				$ 88,000,000
Option to extend, term				1 year
Constellation [Member]
Real Estate and Other Affiliates
Number of units in Class A apartment building to be constructed | item		124
Area Of Land In Downtown Summerlin | a		400
Area of land contributed to the joint venture (in acres) | a		4.5
Fair value of the land contributed to joint venture		$ 3,200,000
Percentage of ownership interest of partners in joint venture		50.00%
Percent Share of Proceeds Upon Sale Of Property		50.00%
Percentage of proceeds in excess of an amount determined by applying a specified capitalization rate to NOI		100.00%
Capitalization rate (as a percent)		7.00%
Percentage of project occupied					87.90%				87.90%
Percentage of project leased					95.20%				95.20%
Constellation [Member] | Calida Group [Member]
Real Estate and Other Affiliates
Percentage of ownership interest of partners in joint venture		50.00%
Payments to Acquire Interest in Joint Venture		$ 3,200,000
Constellation [Member] | Bridge Loan [Member]
Real Estate and Other Affiliates
Non-recourse construction loan		$ 15,800,000
Circle T Ranch and Power Center [Member]
Real Estate and Other Affiliates
Area of land sold | a	72
Equity in earnings										$ 10,500,000
Equity Method Investments | The Summit
Real Estate and Other Affiliates
SID Bonds transferred to a joint venture								$ 1,300,000
Transaction value of the land contributed to joint venture								125,400,000
Value of land contributed to joint venture, price per acre								226,000
Fair value of the land contributed to joint venture								13,400,000
Equity Method Investments | The Summit | Maximum
Real Estate and Other Affiliates
Maximum capital contribution required								$ 30,000,000
Equity Method Investments | Constellation [Member]
Real Estate and Other Affiliates
Future contribution required							$ 1,000,000
One Month LIBOR | m.flats/TEN.M | Construction Loan Payable [Member]
Real Estate and Other Affiliates
Interest rate margin (as a percent)				2.40%